>There is only one select() call (or whatever) at any given time, regardless of >how many timers.
Yes, I do understand this. >Syscalls are thus O(1). Timers are stored in sorted order. When event loop >wakes up it removes timers that have been reached, which is fast because >they're sorted so when you hit one that is still in future you can stop. So >that's pretty scalable. syscalls are O(1). But the constant is non zero. A syscall is still quite expensive. try doing 1 mio. syscalls/sec on any x86 box (Linux, BSD, whatever). DEC Alphas and Itanium might be able to do more, but the context switching overhead of x86 architecture is "huge". But I feel I failed in formulating what I am asking. Could you please correct where my thinking below goes wrong? Let's say I issue 1 mio. timers with expirary times t0, t0+1us, t0+2us, .., t0+1s That is 1 mio. timers expiring in 1us pitch within 1s. That will mean 1 mio. select() syscalls done in 1s each with timeout set to 1us Since it's unlikely that a box supports a rate of 1 mio. syscalls/sec, that means a select with timeout 1us won't return after 1us, but >1us. Twisted will process all timers that have expired in the meantime. But there is no way of letting 1 mio. timers fire in 1us pitch within 1s using a syscall. What I am after is to explicitly _control_ the maximum syscall rate to select() - not simply max. out the box on syscall rate. Like: limit syscall rate to select() at 1000Hz - regardless how many timers I issue per second. In above example, with syscall max set to 1000Hz, each time select() returns 1000 timers would have expired. That's fine. That's what I want. How can I do that? Thanks! Tobias _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
